| 30401 | Txon Partners, LLC | Houston, TX 77057 | Oil & Gas Operator | Jun 2017 |
| 30402 | TXP Operating Company | | Oil & Gas Operator | Jul 1992 |
| 30403 | TXP, Incorporated | San Angelo, TX 76906 | Oil & Gas Operator | Jun 2025 |
| 30404 | Txu Fuel Company | Dallas, TX 75201 | Oil & Gas Operator | May 2004 |
| 30405 | Txu Gas Company | Dallas, TX 75201 | Oil & Gas Operator | Sep 2004 |
| 30406 | Txu Lone Star Pipeline | Dallas, TX 75201 | Oil & Gas Operator | Oct 2003 |
| 30407 | TXX Operating LLC | Shreveport, LA 71133 | Oil & Gas Operator | Jun 2025 |
| 30408 | Ty-Tex Exploration, Inc. | Tyler, TX 75711 | Oil Operator | Dec 2000 |
| 30409 | Tyco Incorporate | | Oil & Gas Operator | Oct 1995 |
| 30410 | Tyco Oil Co. | | Oil Operator | Jan 2025 |
| 30411 | Tyco Operating Co. | Archer City, TX 76351 | Oil & Gas Operator | Jun 2025 |
| 30412 | Tyco, Inc. | Independence, KS 67301 | Oil & Gas Operator | Jan 1998 |
| 30413 | Tygr Operating Company, LLC | | Oil & Gas Operator | Nov 2024 |
| 30414 | Tyl Oil | Canon City, CO 81212 | Gas Operator | May 1994 |
| 30415 | Tyler Enterprises Inc | Bristow, OK 74010-3192 | Oil & Gas Operator | Feb 2004 |
| 30416 | Tyler Oil & Gas Inc. | Tyler, TX 75702 | Oil & Gas Operator | Sep 2004 |
| 30417 | Tyler Oil Company | Billings, MT 59104-3203 | Oil & Gas Operator | Nov 2019 |
| 30418 | Tyler Production, LLC | | Oil & Gas Operator | Jul 2013 |
| 30419 | Tyler Rockies Exploration LTD | Tyler, TX 75710-0119 | Oil & Gas Operator | Mar 2025 |
| 30420 | Tyler, Scott A | | Oil & Gas Operator | Mar 2025 |
| 30421 | Tyler, Steven Lee | | Oil Operator | May 2014 |
| 30422 | Tyluka Operations, LLC | Hays, KS 67601 | Oil Operator | Nov 2024 |
| 30423 | Tyner Texas Operating Company | Dallas, TX 75248 | Oil & Gas Operator | Jun 2025 |
| 30424 | Tyrex Oil Company | Casper, WY 82602 | Oil & Gas Operator | May 1997 |
| 30425 | Tyro Oil Develop | | Oil Operator | Jul 1991 |
| 30426 | Tyrok | | Oil & Gas Operator | Nov 2010 |
| 30427 | Tysco Oil And Gas Corp. | | Oil & Gas Operator | Dec 2024 |
| 30428 | Tyson Gary | Hobart, OK 73651-6413 | Oil & Gas Operator | Mar 2018 |
| 30429 | Tyson Oil Co. | | Oil Operator | Jan 2025 |
| 30430 | Tyson Olan | Hobart, OK 73651-6413 | Oil & Gas Operator | Apr 2015 |
| 30431 | Tytan Operating Company LLC | Edmond, OK 73083-3794 | Oil & Gas Operator | May 2016 |
| 30432 | U Bee Tea Production LLC | Culbertson, MT 59218 | Oil & Gas Operator | Mar 2025 |
| 30433 | U R C C | | Oil & Gas Operator | Jun 1991 |
| 30434 | U S Department Of Energy | | Oil & Gas Operator | Apr 1999 |
| 30435 | U S Drilling Company Inc | Holdenville, OK 74848-0913 | Oil & Gas Operator | Mar 2017 |
| 30436 | U S Energy Corp. Of Amer. Inc. | Ranger, TX 76470 | Oil & Gas Operator | Jun 2025 |
| 30437 | U S Exploraton Liq Trust | | Oil & Gas Operator | Oct 1994 |
| 30438 | U S Liquids Of La., L.P. | | Oil Operator | Apr 2014 |
| 30439 | U V Industries | | Oil & Gas Operator | Jan 1993 |
| 30440 | U-N-I Exploratio | | Oil & Gas Operator | Dec 1990 |
| 30441 | U-N-I Exploration & Development, Inc. | Yates Center, KS 66783 | Oil & Gas Operator | Jan 2003 |
| 30442 | U. D. Man, Inc. | San Antonio, TX 78212 | Oil & Gas Operator | Jun 2025 |
| 30443 | U. O. C., Inc. | | Oil Operator | Jun 2019 |
| 30444 | U. S. Operating, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Jun 2025 |
| 30445 | U.S. Capital Corp Of Am, Inc. | | Oil & Gas Operator | Aug 1998 |
| 30446 | U.S. Enercorp, LLC | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2004 |
| 30447 | U.S. Enercorp, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2019 |
| 30448 | U.S. Energy Development Corp | Fort Worth, TX 76164 | Oil & Gas Operator | Jun 2025 |
| 30449 | U.S. Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 30450 | U.S. Oil Reclaimers, LLC | | Oil Operator | Jun 2023 |
| 30451 | U.S. Sovereign Oil And Gas, Inc. | Dallas, TX 75355 | Oil & Gas Operator | Jun 2025 |
| 30452 | U.S. Steel Mining Co., Inc. | | Gas Operator | Jan 2000 |
| 30453 | U.S. Steel Mining Co., LLC | | Gas Operator | Oct 2002 |
| 30454 | U.S.A. Plugging Company | Pearsall, TX 78061 | Oil & Gas Operator | Jun 2025 |
| 30455 | U1 Ranch Oil | Houston, TX 77269 | Oil & Gas Operator | Jun 2025 |
| 30456 | Uae Investco 1 (Estill), LLC | Ravenna, KY 40472 | Oil Operator | Dec 2022 |
| 30457 | Uae Investco 2 (Lee), LLC | Ravenna, KY 40472 | Oil Operator | Dec 2021 |
| 30458 | Ubetco, Inc. | Rockdale, TX 76567 | Oil & Gas Operator | Jun 2025 |
| 30459 | Uebelhor, Theodore | | Oil Operator | Dec 2023 |
| 30460 | Uehlin LLC | Oberlin, KS 67749 | Oil Operator | Dec 2024 |
| 30461 | Uhc New Mexico Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2007 |
| 30462 | Uhc Petroleum Corporation | Rocksprings, TX 78880 | Oil & Gas Operator | Jun 2025 |
| 30463 | Uhl Oil Co., Inc. | Bradford, PA 16701 | Oil & Gas Operator | Dec 2023 |
| 30464 | Uhl, Robert | Bradford, PA 16701 | Oil & Gas Operator | Dec 2023 |
| 30465 | Uhls, Jimmie J. | Sedan, KS 67361 | Oil Operator | Sep 2019 |
| 30466 | Uinta Oil & Gas | Roosevelt, UT 84066 | Oil & Gas Operator | Nov 1997 |
| 30467 | Uinta Wax Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2025 |
| 30468 | Uinta-Taylor Fund, LTD | Roosevelt, UT 84066 | Oil & Gas Operator | Nov 2018 |
| 30469 | Uintah Investors LLC | Vernal, UT 84078 | Oil & Gas Operator | Apr 2025 |
| 30470 | Ulatex Oil & Gas Inc. | Nocona, TX 76255 | Oil & Gas Operator | Dec 1998 |
| 30471 | Ullum Oil And Gas Development Corporation, Inc. | Grantsville, WV 26147-0000 | Oil & Gas Operator | Dec 2021 |
| 30472 | Ulrich, William J., Jr. & Connie K. | Elma, NY 14059 | Gas Operator | Dec 2023 |
| 30473 | Ultra Oil & Gas, Inc. | Centerton, AR 72719 | Oil & Gas Operator | Jun 2025 |
| 30474 | Ultra Petroleum (U.S.A.), Inc. | Granbury, TX 76048 | Oil & Gas Operator | Sep 2003 |
| 30475 | Ultra Production Company, LLC | Cedar Bluff, VA 24609 | Gas Operator | Oct 2014 |
| 30476 | Ultra Resources Inc | Houston, TX 77060 | Oil & Gas Operator | Sep 2018 |
| 30477 | Ultramar Oil & Gas LTD | Houston, TX 77060 | Oil & Gas Operator | Jul 1995 |
| 30478 | Ultramar Production Company | | Oil & Gas Operator | Dec 1991 |
| 30479 | Ulysses, City Of | Ulysses, KS 67880 | Gas Operator | Jan 2025 |
| 30480 | Umberham Oil Company Inc | Oklahoma City, OK 73151-4000 | Oil & Gas Operator | Mar 2025 |
| 30481 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 30482 | Umma Resources, LLC | Portland, TX 78374 | Gas Operator | Jun 2025 |
| 30483 | Ummel'S Tank Ser | | Oil Operator | Sep 1994 |
| 30484 | Unbridled Resources, LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2025 |
| 30485 | Unc Texas Incorp | | Gas Operator | May 1987 |
| 30486 | Underground Energy Inc. | | Oil & Gas Operator | Mar 2025 |
| 30487 | Underwood Oil & Gas | Casper, WY 82602 | Oil & Gas Operator | Apr 2025 |
| 30488 | Underwood Oil And Gas LLC | Chandler, OK 74834-1414 | Oil & Gas Operator | Mar 2025 |
| 30489 | Underwood, Donald D. Dba Mustang Oil Co | Salem, WV 26426 | Oil & Gas Operator | Dec 2020 |
| 30490 | Underwood, Jim | Graham, TX 76450 | Oil & Gas Operator | Mar 2018 |
| 30491 | Underwood, Rip C | Amarillo, TX 79101 | Gas Operator | Sep 1963 |
| 30492 | Unger Well Drilling Corp | Dennison, OH 44621 | Oil & Gas Operator | Dec 1999 |
| 30493 | Uni Production Company, Inc. | | Oil & Gas Operator | Apr 1988 |
| 30494 | Unicon Producing Company | Houston, TX 75252 | Gas Operator | Mar 1994 |
| 30495 | Unicorn Drilling Inc | Cody, WY 82414 | Oil Operator | Dec 1998 |
| 30496 | Unicorn Energy, Inc. | Elgin, TX 78621 | Oil & Gas Operator | Jun 2025 |
| 30497 | Unicorn Oil & Gas Co Inc | Dorset, OH 44032 | Oil & Gas Operator | Dec 1993 |
| 30498 | Unifid Oil & Gas Corp. | | Oil & Gas Operator | Mar 1994 |
| 30499 | Unified Oil & Gas Corp. | Snyder, TX 79550 | Oil Operator | Jun 2025 |
| 30500 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Jun 2012 |